Now if NGC would offer price points for coins with either or both of those designations.. or is there a rough estimate for them based on the specific designation...
The "FS" designation existed before this coin was slabbed, but NGC did not differentiate between 5FS and 6FS at the time this coin was slabbed. All coins designated as "FS" by NGC before February 16, 2004 were assumed to have 6FS. The 5FS part was added after that date (see link http://www.ngccoin.com/news/viewarticle.aspx?NewsletterNewsArticleID=250). I'm not sure if it would make 5FS designation today or not, but I see some bridging and a possible scuff under the first pillar, so I would doubt it. See larger pic: